aww that sucks ;;;
i normally dont even work with fantasy elements so i can only imagine how much working on a full on fantasy world would be terrifying
maybe if u could be like,, "the resolution to that turns up in X pages !"
or try and establish rules before using a system?
i.e. if the characters have a 'mana' type magic system where their magic slowly runs out and they have to regain it via food/rest, you can show an introduction scene where someone's run out of mana and gets hurt in battle due to it.
obviously whatever works for your comic might be more difficult, but you could also hold off on scenes until you've explained how they work?